1. Catapult
TL A
Team 24 (Hybrid)
David Lakin Troy Moon
Alexandra Cruz David Khonsary

2. Initial
Design
Trebuchet first

Decided to take risk with

ballista

3. Problem
s
Dimensional

requirements
 (33”W x 81”H x 158”L)
Projectile size

Friction


4. Materia
ls
Wood (oak/pine)

Manila rope

Metal rods

Bolts/Screws

Wheels


5. Constructio
n
Fac

e

6. Constructio
n
Shaf

t

7. Constructio
n
Base/Brid

ge

8. Finished
Product
Preliminaries

“De o
adb lt”

9. Collapsibility
Two joints/three

parts
Body, Bridge, Base


10. Final Design Overview

11. First Test Runs
Trial Launch Distance in Time in Modifications
Number Angle in Feet (nearest Seconds
Degrees foot)
1 45 0 0 Initial design
2 45 9 1.4 Modification of shaft area:
Deletion of trolley, addition of “pouch”
to carry basketball forward,
“flattening” of arms, change in bow
string position.
3 30 15 1.7 Lubrication
4 45 13 2.0 none
5 45 16 2.2 Retightening of ropes
6 50 15 2.0 Retightening of ropes

12. Preliminary/Final Results
Distance Accuracy Assembly/Disassembly
Time
Saturday 10 ft N/A Assembly: 17 sec
Disassembly: 20 sec
Saturday 7 ft N/A
Saturday 15 ft N/A Assembly: 15 sec
Monday 16 ft 28 ft
Disassembly: 19 sec

13. Final
Limitations
Ratio of Projectile Size to

Arm Size/Face Size
Shaft length dependent upon

arm length
Torsion rope strength

dependent upon face size

14. Reference
s
Alchin, Linda K. (2008a). Ballista. Retrieved March
22,2009, from
www.middle-ages.org.uk/ballista.htm
Alchin, Linda K. (2008b). Roman Siege Weapons.
Retrieved March 22, 2009, from
http://www.roman-colosseum.info/roman-weapons/ro
Hoisington, J. (2005, March 21). Ballista Physics.
Retrieved March 22, 2009, from
http://ffden-2.phys.uaf.edu/212_spring2005.web.dir/
L., Danielle & M., Nirvana. (2004). Optimal Launch
Angles. Retrieved April 3, 2009 from
http://www.umbc.edu/upwardbound-mathscience/laun
Smith, K. & Smith, P. (2008). Ballistae. Retrieved Feb
25, 2009 from http://
siegethedayinc.com/ballistae.aspx